2003-01-05 04:00:00 PDT Los Angeles -- For seven years Lawrence O'Donnell Jr. was privy to Washington's shrewdest power brokers. Beginning in 1989, he served four years as senior adviser to New York Sen. Patrick Moynihan and in 1992 became Democratic chief of staff for the Senate Finance Committee.

All the while, O'Donnell was stockpiling some great storytelling material.

"I carried a reporter's notebook around all the time," he says. "I'd be taking notes at our meetings about this thing costing $33 billion and that thing costing $15.5 billion. But I was also taking a different kind of note, about behaviors and appearance and stylistic choices these people were making."

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O'Donnell brings his Beltway savvy to prime time this winter as executive producer of "Mister Sterling." The series stars Josh Brolin as an idealistic lawyer teaching in the prison system. On the strength of his famous name -- his dad is California governor -- he's appointed to the U.S. Senate when the incumbent dies. By the end of the first episode, Sterling will have seats on two powerful committees and be ready to shake up the status quo.

O'Donnell produced "The West Wing" for its first two seasons but dismisses any comparisons between his new show and NBC's other political drama.

"The White House and the Senate are two different arenas," he says, enjoying a bowl of cornflakes in the parking lot of the Los Angeles production lot where "Mister Sterling" is filmed. " 'Law & Order' and 'NYPD Blue' are about exactly the same subject, but they're very different shows. So even though in Washington the Senate and the White House are only a couple of miles apart, in storytelling terms they are worlds apart."

Learning about those worlds was the last thing on Brolin's mind when he was first sent the "Mister Sterling" pilot script. Though his father, James Brolin,

is married to staunch Democrat Barbra Streisand, Brolin had zero interest in partisan politics. "I didn't appreciate 98 percent of anything involving politics before," says Brolin, who lives with his family on a ranch near San Luis Obispo.

Sitting on a set copied in exacting detail from an actual subcommittee hearing room in the Dirksen Building in Washington, Brolin acknowledges, "Unless it was something local that very directly affected me or my family, like education, because I have kids, I knew nothing in the more global sense about politics and wasn't really interested in knowing anything."

In fact, Brolin initially turned down the offer to star in the series. Having done network dramas "Winnetka Road" and "The Young Riders," he was in no hurry to take on another conventional leading-man role.

"I thought the pilot was a little safe. Were they going to allow this character, who could obviously be a hero like 'Mr. Smith Goes to Washington,' to falter, to fail during a speech, to say the wrong things?"

Referring to his star turn in the 2000 Broadway revival of a Sam Shepard play, Brolin says, "I've always kind of fought against that leading-man thing, which is why I did 'True West.' Or (the movie) 'Flirting With Disaster' -- they are off kilter, and they're so much more interesting to me."

Brolin's agent persuaded him to reconsider. "He said, 'Don't be a schmuck --

go meet the guy.' "

So Brolin sat down with O'Donnell and realized that his boss-to-be would bring a unique perspective to the series.

"With Lawrence, you get this guy who really knows what went on in the Senate, and he's creating a fictional show based on that. How great is that? Aaron Sorkin is not in that position. He's a dramatist. But Lawrence O'Donnell has the benefit of actually having been a major part of all that."

Preparing for the role, Brolin observed Congress in action and was not impressed.

"I went to Washington and met with some of the senators," he recalls. "Everybody I met had that great 'How ya doin'!' smile and could make you feel like you're the only one on the planet. All that's fine and dandy, but what's really happening and who's screwing who, and who's really talking s-- about the other person?

"You see Daschle get up and give this great speech: 'We won't put up with this and we won't do that,' and two days later he's in cahoots with Bush, and you go, 'What the . . .? Did I not just hear one of the greatest speeches I ever heard? And you realize there's so much bull-- on CNN and MSNBC and FOX, and it's all theater. I want to know what's really happening."

Not that the show will get too obsessive about politics, per se. O'Donnell intends for Capitol Hill to serve as a fresh setting for "Mister Sterling" but says he has no interest in espousing his own views on the show.

"Political issues don't interest me at all as part of dramatic television writing," he says. "I have absolutely no mission here to push one political position over another. Characters will win some, they'll lose some, but that's not what the show will be about."

"I remember when I first started working in the Senate, it was February and we were having a conversation about something we wanted to do, and someone said, 'Well, there's not enough time to do that this year.' I thought, 'How can that possibly be?' "

O'Donnell eventually grew savvy to Congress' byzantine procedures and even came to respect its nuances.

"I came to understand all the different processes involved in getting a piece of legislation from ground zero all the way to the president's signature.

Once you've been at it for a while, the notion of doing any form of that in less than a year is hard to conceive.

"The longer you're inside the bubble, the more it makes sense to you. But Sterling will not be comfortable with those explanations and he will not be comfortable trying to make sense of the nonsense of Washington life."

Brolin says the pilot episode tested well with preview audiences, and he thinks he knows why.

"It's because they see a guy who's human. It's not just learning about the Senate -- it's about a guy who could basically be almost anybody in America being thrown into this situation, and then exploring what would happen if he stuck with his integrity and his morals. What would happen if he didn't play into the bureaucracy? Is there any kind of possibility that he could actually prevail?"